Speaker
Dr
Ladislav Hluchy
(Institute of Informatics, Slovakia)
Description
We present an IST project of the 6th Framework Programme, aimed to create a
distributed framework for multi-risk assessment of natural disasters that will
integrate various models for simulation of forest fire behavior and effects, flood
modeling and forecasting, landslides and soil erosion simulations. Also, a
distributed repository with earth observation data, combined with field
measurements is being created, which provides data to all models using data format
conversions when necessary. The entire system of models and data will be shaped
further as a multi-risk assessment and decision support information platform.
There are 6 partners in the project from Greece, Portugal, France, Spain, United
Kingdom and Slovakia.
The system targets both Linux and Windows based simulation models. The Linux based
models are meteorological, hydrological and hydraulics models of the flood
forecasting application, with meteorology and hydraulics being a parallel MPI
tasks. Other applications - forest fire behaviour and effects, landslides and soil
erosion - are sequential Windows jobs. These simulations are being merged into one
system that uses common distributed data warehouse containing data for pilot areas
in France, Portugal and Spain. User should be able to transparently run these
simulations from the application portal, reuse data between models and store the
results annotated with metadata back to the data warehouse.
In order to create a virtual organization (VO) for multi-risk assessment of
natural disasters a grid middleware had to be chosen to be used on computing
resources. Because each of the partners provides some of the services on his own
resources that run both Linux and Windows, we could not use available middleware
toolkits like LCG or Globus as they are focused on Unix/Linux platform. For
example, they build their data services on the GridFTP standard for data transfer.
However, there are stable implementations of GridFTP just for Unix based systems,
ignoring the world of Windows. Therefore, we have decided to implement our own data
transfer and job submission services. In order to keep some compatibility with the
established grid infrastructures, we have chosen the Java implementation of the
WSRF specification by the Globus alliance as a base for our services. It is an
implementation of core web (grid) services with security, notifications and other
features and it is capable of running on both Windows and Linux. Each of the system
components - simulation models, data providers, information services or other
supporting services - is exposed as a web service. We use WSRF as a standard basic
technology that both serves as an implementation framework for individual services
and also enables to glue the individual components together.
The whole system will be accessible via a web portal. We have chosen GridSphere
portal framework for its support of portlet specification. Application specific
portlets will allow users to invoke all the simulation services plugged into the
system in application specific manner; for example using maps for selection of a
target area or an ignition points for forest fire simulations. There will be
portlets for browsing results, metadata describing those results, testbed
monitoring and others.
So far, two services have been implemented on top of the WSRF: Data Transfer
service and Job Submission service.
Data Transfer service serves as a replacement for widely used GridFTP tools. The
main disadvantage of GridFTP is that implementations are available just for the
UNIX platforms. In Medigrid, Windows is a platform of several models and porting
them to UNIX world was not an option for developers.
Data Transfer service provides data access policies definition and enforcement in
terms of access control lists (ACLs) defined for each data resource - a named
directory serving as a root directory for given directory tree accessible via the
service. It has been integrated with central catalog services we have deployed:
Replica Location Service - a service from Globus toolkit for which we had to
implement WSRF wrapper - and Metadata Catalog Service - a service from Gryphyn
project that is just a plain web service.
Job Submission service provides the ability to run the executable associated to it
with parameters provided with job submission request. Currently, jobs are started
locally using the "fork" mechanism on both Linux and Windows. Requests are queued
by the service and run in the "first come first served" manner in order not to
overload the computer. In near future we plan to add job submission forwarding from
the service to a Linux cluster and later on to a classical grid.A base of the
project's portal has been set up based on the Gridsphere portal framework. Thus far
portlets have been developed for browsing the contents of the metadata catalog
service and a portlet for generic job submission.
As it can be seen in this project, the world of simulations is not limited to the
Unix platform and support for Windows applications is desired but missing.Therefore
we think it may be important for the EGEE project to try to suppport Windows users
in order to widen its reach and appeal.
Summary
We present an IST project of the 6th Framework Programme, aimed to create a
distributed framework for multi-risk assessment of natural disasters that will
integrate various models for simulation of forest fire behavior and effects, flood
modeling and forecasting, landslides and soil erosion simulations. Also, a
distributed repository with earth observation data, combined with field
measurements is being created, which provides data to all models using data format
conversions when necessary. The entire system of models and data will be shaped
further as a multi-risk assessment and decision support information platform.
Author
Dr
Ladislav Hluchy
(Institute of Informatics, Slovakia)
Co-author
Branislav Simo
(Institute of Informatics, Slovakia)
